Gear reduction assembly

ABSTRACT

In a first embodiment of the invention, a gear ratio multiplier has directly cooperating gears which serve to rotatably connect an output shaft to an output shaft through an intermediate shaft. The input and output shafts have parallel axes of rotation and extend, respectively, from seals in opposite sides of a housing. The inner ends of the input and output shafts are spaced from one another and are each provided with a pinion gear. The intermediate shaft is rotatably carried between the pinion gears and has an axis of rotation positioned at right angles to the axes of rotation of the input and output shafts. A pair of differently sized ring gears having different numbers of teeth are affixed on the intermediate shaft. The pinion gear on the input shaft engages the relatively smaller ring gear on the intermediate shaft whereas the pinion gear on the output shaft engages the relatively larger ring gear on the intermediate shaft. In this first illustrated embodiment, the gear ratio multiplier is utilized in the power train of a motor vehicle and is positioned between the transmission and propeller shaft to modify the gear ratio between the engine and one or more drive axles. Other embodiments of the invention utilize other gear assembly arrangements such as, but not limited to, sun and planetary gear arrangements and ring gear arrangements. While a motor vehicle is shown, this use of a gear ratio multiplier is applicable to other devices or machines such as, but not limited to, water vehicles, helicopters, construction machinery or any other engine driven device.

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application is a continuation-in-part of application Ser.No. 08/912,397, filed Aug. 18, 1997.

FIELD OF THE INVENTION

[0002] The present invention relates generally to machine elements ormechanisms and, in particular, to a gearing system having directlycooperating gears with intersecting axes of rotation.

BACKGROUND OF THE INVENTION

[0003] A transmission provides different gear ratios between the engineand drive wheels of a typical land vehicle. The transmission enables thevehicle to accelerate from rest up to a maximum speed through a widespeed range while the engine operates efficiently. In most applications,the transmission is positioned in the vehicle power train between theengine and the propeller shaft. The engine's power flows through thetransmission and propeller shaft and is delivered to the differentialand drive axles.

[0004] Most vehicle transmissions operate within a preset range of gearratios. This is a problem for special purpose vehicles, such as pickuptrucks, used for carrying or towing heavy loads. Excessive engine andtransmission wear, fuel consumption, and operating costs can result fromgear ratios that are set too high at the time of their manufacture. Aneed, therefore, exists for an “add-on” assembly which can be easily andeconomically inserted into the power train of a vehicle for reducing thegear ratio between the engine and drive axles. Moreover, there is needin passenger cars, boats, ships, helicopters, small trucks, heavytrucks, front wheel drives and motorcycles for improved efficiency andreduction in air pollution which results from improved efficiency.

SUMMARY OF THE INVENTION

[0005] In view of the limitations associated with known vehicletransmissions, it is a principal object of the invention to provide agear reduction assembly which can be operatively connected between afactory installed transmission and propeller shaft to increase ratio andtorque, increase the gear ratio and torque between the engine and driveaxles of the associated vehicle.

[0006] It is another object of the invention to provide a gear reductionfeaturing spiral bevel gears. The tooth inclination of such gears bringsmore teeth in contact at any one time than with equivalent straightbevel gears. The result is smoother and quieter operation, particularlyat high speeds, and greater load-carrying ability than with straightbevel gears.

[0007] It is a further object of the invention to provide a gearreduction assembly of the type described which, during use, willincrease torque imparted to the drive axles, decrease fuel consumption,increase engine and transmission life, and reduce vehicle operatingcosts.

[0008] It is an object of the invention to provide improved elements andarrangements thereof in a gear reduction assembly for the purposesdescribed which is lightweight in manufacture, inexpensive inconstruction and installation, and fully effective in use.

[0009] In its broadest aspect, the present invention is directed to theconcept of positioning a gear ratio multiplier between a transmissionand drive shaft or propeller shaft of a device powdered by an internalcombustion engine, such as land, water or air vehicles, or any type ofdevice or machine.

[0010] More specifically, the gear ratio multiplier comprises a gearassembly disposed between an engine and a driven device, wherein thegear assembly first increases torque by decreasing shaft speed (RMP)within the assembly and then increases shaft speed (RPM) beforetransferring that increased shaft speed to the driven device.

[0011] Briefly, the gear ratio multiplier in accordance with a firstembodiment of this invention achieves the intended objects by featuringdirectly cooperating gears which serve to rotatably connect an inputshaft to an output shaft through an intermediate shaft. The inner endsof the input and output shafts are spaced from one another and are eachprovided with a substantially identical pinion gear. The intermediateshaft is rotatably carried between the pinion gears and has a pair ofdifferently sized ring gears. The larger ring gear includes more teeththan the smaller ring gear. The pinion gear on the input shaft engagesthe smaller ring gear whereas the pinion gear on the output shaftengages the larger ring gear. When rotated, the input shaft drives theoutput shaft with an accompanying mechanical advantage.

[0012] While the aforementioned first embodiment was employed in asuccessful application of the invention, it is also within the scope ofthis invention to employ other types of gear assembly arrangements suchas, but not limited to, planetary gear and ring gear arrangements.

[0013] The foregoing and other objects, features and advantages of thepresent invention will become readily apparent upon further review ofthe following detailed description of the various preferred embodimentsas illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention may be more readily described withreference to the accompanying drawings, in which:

[0015]FIG. 1 is a cross-sectional view of a first embodiment of a gearreduction assembly in accordance with the present invention;

[0016]FIG. 2 is a diagrammatic view of a vehicle power train includingthe transmission of FIG. 1;

[0017]FIG. 3 is a cross-sectional view of a second embodiment of a gearreduction assembly in accordance with the present invention;

[0018]FIG. 4 is a cross-sectional view of a third embodiment of a gearreduction assembly in accordance with the present invention;

[0019]FIGS. 5A and 5B are cross-sectional, perspective views of a fourthembodiment of a gear reduction assembly in accordance with the presentinvention;

[0020]FIG. 6 is a cross-sectional view of a fifth embodiment of gearreduction assembly in accordance with the present invention;

[0021]FIG. 7 is a graph plotting load (in foot-pounds) for a stockvehicle and for a vehicle equipped with a gear reduction assemblyaccording to the present invention, as well as horse power for a stockvehicle and a vehicle equipped with the reduction gear assembly, bothover a 3 minute time interval;

[0022]FIG. 8 is a bar graph showing comparisons of hydrocarbon, carbonmonoxide and nitrous oxide emissions for a stock vehicle, the governmentstandard and applicant's invention;

[0023]FIG. 9 is a chart showing emissions for vehicle not equipped witha gear ratio multiplier; and

[0024]FIG. 10 is a chart showing emissions for a vehicle equipped with agear ratio multiplier according to the present invention.

[0025] Similar reference characters denote corresponding featuresconsistently throughout the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0026] Referring now to the FIGS. 1 and 2, a gear ratio multiplierassembly in accordance with the present invention is shown at 10. Theassembly 10 includes four, directly cooperating gears 12, 14, 16, and 18which serve to rotatably connect an input shaft 20 to an output shaft 22through an intermediate shaft 24. The input shaft 20 and output shaft 22have parallel axes of rotation and extend, respectively, from seals 26and 28 in opposite sides of a housing 30. The inner ends of the inputand output shafts 20 and 22 are spaced from one another and are providedwith substantially identical pinion gears 12 and 18. The intermediateshaft 24 is rotatably carried between the pinion gears 12 and 18 and hasan axis of rotation positioned at right angles to the axes of rotationof both the input shaft 20 and output shaft 22. A pair of ring gears 14and 16, having different numbers of teeth, are affixed in a back-to-backrelationship on the intermediate shaft 24. The pinion gear 18 on theinput shaft 20 engages the relatively smaller, ring gear 16 on theintermediate shaft 24 whereas the pinion gear 12 on the output shaft 22engages the relatively larger, ring gear 14 on the intermediate shaft.When rotated during use, the input shaft 20 drives the output shaft 22with an accompanying mechanical advantage which increases the gear ratioand torque while decreasing engine RPM.

[0027] The input shaft 20 is rotatably supported within the housing 30by a pair of roller bearings 32 spaced along its length. The inner races34 of the bearings 32 are maintained at a fixed distance from each otherby a tubular spacer 36 encircling the input shaft 20. The outer races 38of the bearings 32, however, are held apart by stops 40 projectinginwardly from the side walls of the housing 30. A pair of lock nuts 42and 44 threaded onto the outer end of the input shaft 20, along withadjacent washers 46 and 48, serve to drive the bearings 32 together andfix the position of the pinion gear 18 within the housing 30. Finelongitudinal adjustment of the position of the pinion gear 18 isachieved by varying the thickness of the washer 50.

[0028] Like the input shaft 20, the output shaft 22 is rotatablysupported by spaced roller bearings 52. The inner races 54 of thebearings 52 are maintained in position by a tubular spacer 56 whereasthe outer races 58 are supported by stops 60. Similarly, lock nuts 62and 64 and washers 66 and 68, secured to the output shaft 22, fix theposition of the pinion gear 12. A washer 70 of predetermined thicknessis positioned on the output shaft 22 and against the pinion gear 12 tofinely adjust the position of the gear 12.

[0029] The intermediate shaft 24 is rotatably journaled at its oppositeends in roller bearings 72. Shoulders 76 on the intermediate shaft setthe respective positions of the inner races 78 of the bearings 72.Spacing washers 80, of predetermined thickness and located between theshoulders 76 and inner races 78, permit the vertical positioning of theintermediate shaft 24 to be adjusted as desired by a user. Stops 82projecting inwardly from the side walls of the housing 30 retain theouter races 84 of the bearings 72.

[0030] Although the pinion gears 12 and 18 are preferably machined ontothe ends of the shafts 20 and 22 so as to form an integral part thereof,the ring gears 14 and 16 are preferably releasably secured to theintermediate shaft 24. As shown, a pair of ring gear cranks 86 and 88are connected by means of grooves 90 to the intermediate shaft 24 forrotation therewith. Bolts 92 secure the ring gears 14 and 16 to thecranks 86 and 88. A disk-shaped spacer 94 separates the cranks 86 and 88as well as the ring gears 14 and 16.

[0031] Openings are provided in the housing 30 for adding andwithdrawing lubrication oil. An opening, normally closed by bolt 96, inthe top of the housing 30 is provided for filling the housing 30 withoil prior to normal use of the assembly 10. An opening, closed by bolt98, in the bottom of the housing 30 permits used oil to be drained fromthe housing 30.

[0032] Installation of the assembly 10 in a vehicle unequipped with suchis straight forward and illustrated diagrammatically in FIG. 2. Thepropeller shaft 100 of the vehicle is first removed and shortenedsomewhat using conventional machine tools and processes. Next, the inputshaft 20 is aligned with the transmission 102 and is joined to it withconnector 103. The housing 30 is then secured by any suitable means tothe undercarriage 105 of the vehicle. Finally, the shortened propellershaft 100 is joined to the output shaft 22 of the assembly 10 usingconnector 107. When the vehicle engine 104 is now energized to drive thetransmission 102, power will flow through the assembly 10, propellershaft 100, differential 106 and drive axles 108 to drive wheels 110. TheR.P.M.s between the engine 104 and drive axles 108 is permanentlyreduced by inclusion of the assembly 10 in the vehicle power train.

[0033] While the invention has been described with a high degree ofparticularity, it will be appreciated by those skilled in the art thatnumerous modifications and substitutions may be made thereto. Forexample, the gear ratio provided by the gears 12, 14, 16 and 18 islargely a matter of choice and may be varied as desired.

[0034] Referring now to FIG. 3, there is shown a second embodiment of areduction gear assembly 30, identified generally by a numeral 200. Thereduction gear assembly 200 is a planetary gear assembly within ahousing 201 comprising an input shaft 202 which is coupled to the engineof FIG. 2 by a coupling 103 through the transmission 102 (see FIG. 2).The input shaft 202 is connected to a drum gear 204 having internalteeth 206. The internal teeth 206 of the drum gear 204 mesh withplanetary gears 208 which are mounted on a frame 210 which is journaledby a shaft 212 to rotate freely with respect to the drum gear 204 fixedto the input shaft 202. The planetary gears 208 mesh with a sun gear214, while the mounting shafts 216 of a frame 210 drive a hub 218 whichis supported by a first set of bearings 220 in the frame 204 and issupported with respect to the housing 201 by bearings 222. The hub 218has a spur gear 230 fixed thereto which is supported on a shaft 232. Thespur gear 230 has teeth 232 which mesh with the teeth of a pinion gear234. Pinion gear 234 drives an output shaft 236. The output shaft 236 iscoupled by a connector 107 to the propeller shaft 100 of the vehicleshown in FIG. 2.

[0035] Referring now to FIG. 4, where a third embodiment 300 of thespeed reducing gear is illustrated, an input shaft 302 is journaled in ahousing 303 and is unitary with a drum gear 304. In the drum gear 304has internal teeth 305 which mesh with three planetary gears 306. Thethree planetary gears 306 are mounted on a frame 308 so configured toallow the planetary gears to rotate on shafts 310 which are part of theframe. The shafts 310 are mounted in the stabilizing plate 312 which isjournaled by bearings 314 on an output shaft 316. At one end of theoutput shaft 316 there is fixed the sun gear 320. The sun gear 320 isdriven by a second set three of planetary gears 322 which in turn aredriven by a first set of planetary gears 306 to rotate the spur gear 320with which the second set of planetary gears 322 are meshed. This drivesthe output shaft 316 to rotate within a bearing 328 mounted in an endplate 330 of the housing 303. The output shaft 316 is coupled by acoupling of 107 to a propeller shaft 100 when the arrangement is used todrive a vehicle (see FIG. 2).

[0036] Referring now to FIGS. 5A and 5B which when combined illustrate afourth embodiment of the invention, a reduction gear 400 is mounted in ahousing 401 which is enclosed by a first end plate 402. The end plate402 has journaled therein an input shaft 404 which is sealed by frontoil seal 406. The input shaft 404 is fixed to a drum 408 which is inturn unitary or integral with ring gear 410. Consequently, as the inputshaft 404 rotates the ring gear 410 rotates with internal gear teeth 412thereof meshing with pinion 414. The pinion 414 is journaled to anL-shaped support strut 416 by a shaft 418 which is received in a bearing420 also mounted in an L-shaped support strut 416. The L-shaped supportstrut 416 is bolted to the front end 424 of the housing 401. Preferably,the housing 401 includes a ventilator 440, a lubrication fill plug 442and a lubrication drain plug 444.

[0037] The pinion 414 is fixed to the shaft 418 which is journaled by abearing 432 in the front end 430 of the housing 401. An oil seal 434keeps the gear oil within the housing 401 contained therein. Aprojecting portion 436 of the shaft 418 forms the output shaft of thegear 400. The output shaft 436 is then coupled by coupling a 107 to apropeller shaft 100 of the vehicle shown in FIG. 2.

[0038] Referring now to FIG. 6, a fourth embodiment 500 of the reductiongear 500 is disclosed in which an input shaft 502 which is journaled ina housing 503 by the roller bearing 504 is fixed to a sun gear 506. Thesun gear 506 meshes with a plurality of planet gears 508 which may be,for example, 2, 3, or 4 in number, which planet gears are mounted on ashaft 510 supported by an intermediate bearing 512. The sun gear 506drives the planetary gears 508 to rotate the shaft 510, and the shaft510 is coupled to a second set of second planet gears 514. The secondset of planetary gears 514 have diameters larger than the first set ofplanetary gears 508. This second set of planetary gears 514 are fixed onthe shaft 510 by L-shaped brackets or a flange 516. The second set ofplanetary gears 514 drive a second sun gear 520 which is fixed to anoutput shaft 524 journaled in bearings 526. Referring again to FIG. 2,when the gear assembly 500 is mounted in a vehicle, then the input shaft502 is coupled by the coupling of 103 to the transmission 102 and theoutput shaft 524 is coupled by the coupling of 107 to the propellershaft 100.

[0039] It is emphasized that while this arrangement has been tested onand is suitable for road vehicles such as the rear wheel drive vehicleof FIG. 2, it is also usable with front-wheel drive vehicles wherein oneof the gear ratio multiplier assemblies shown is disposed between thetransmission of the front-wheel drive vehicle and each of the shaftsthat drive the front wheels, i.e., two gear boxes are used. In addition,the gear assemblies shown in the embodiments of this invention areincorporated directly in an automatic transmission between the output ofthe automatic transmission and propeller shaft or other drive shaftscoupled with the driving wheels of a vehicle.

[0040] While the gear reduction assembly concept disclosed herein hasthus far been successfully tested in pickup trucks, it is emphasizedthat the principles and concepts herein are utilized also in passengervehicles, boats such as pleasure boats, large ships, helicopters, lighttrucks and heavy trucks, motorcycles and construction equipment. Whilethese are specific examples with which the present invention is used,the present invention may be also utilized in other types ofengine-driven devices.

[0041] It is further emphasized that the units can be made using spurgears, spiro-bevel gears, straight bevel gears, or other vehicle gearcombinations.

[0042] Referring now to FIG. 7, there are shown the results of a 3minute dynometer test at 71 MPH comparing torque and horsepower for avehicle using the gear ratio multiplier 10 of FIGS. 1 and 2 and for thesame vehicle not using the gear ratio multiplier. The horsepower notusing the gear ratio multiplier 10 is represented by curve 700 and hasan average value of 37.6 hp, while the horsepower using the gear ratiomultiplier 10 is represented by the curve 701 and has an average valueof 41.7 hp. Use of the gear ratio multiplier 10 results in a horsepowergain of 5.1 hp. The torque not using the gear ratio multiplier isrepresented by curve 702 and has a value of 20.0 ft-lbs, while thetorque using the gear ratio multiplier 10 is represented by the curve703 and has an average value of 21.52 ft-lbs, resulting in an averagetorque gain for 1.52 ft-lbs.

[0043] Referring now to FIG. 8, the bar graph shows emission reductionsof 34.72% in hydrocarbons, 40.57% in carbon monoxide and 21.50% innitrous oxide using the gear ratio multiplier 10 represented by bars710, 711 and 712, respectively, as compared to bars 713, 714 and 715 forthe same vehicle not using the gear ratio multiplier.

[0044] Referring now to FIG. 9 and 10, for the same vehicle, it is seenthat the hydrocarbon, carbon monoxide and nitrous oxide emissions aresubstantially reduced, while miles-per-gallon (fuel economy) issubstantially increased.

[0045] It is to be understood that the present invention is not limitedto the sole embodiments described above, but encompasses any and allembodiments within the scope of the following claims.

What is claimed is:
 1. A power train for engine driven devices,comprising: an internal combustion engine; a transmission operativelyjoined to said internal combustion engine; a gear ratio multiplierassembly having an input shaft geared to an output shaft so that onerotation of said input shaft will result in more than one rotation ofsaid output shaft, and said input shaft being joined to saidtransmission so as to be rotated thereby; a propeller shaft having afirst end, joined to said output shaft for rotation therewith, and asecond end; a differential operatively joined to said second end of saidpropeller shaft; and, a pair of drive axles adapted for rotation by saiddifferential and extending therefrom.
 2. The power train according toclaim 1 wherein said gear multiplier assembly further comprises: a firstpinion gear positioned on said input shaft; a second pinion gearpositioned on said output shaft; the axes of rotation of said inputshaft and said output shaft being parallel; an intermediate shaftpositioned between said first pinion gear and said second pinion gear,the longitudinal axis of said intermediate shaft being positioned atright angles to the respective axes of rotation of said input and outputshafts; a first ring gear positioned on said intermediate shaft forrotation therewith and cooperatively engaged with said first piniongear; a second ring gear positioned on said intermediate shaft forrotation therewith adjacent said first ring gear and cooperativelyengaged with said second pinion gear; said first pinion gear having aselected number of teeth as said second pinion gear; and said first ringgear having a lesser number of teeth than said second ring gear when thefirst pinion gear and second pinion gear have the same number of teeth.3. The power train according to claim 2 wherein said first and secondpinion gears and said first and second ring gears are spiral bevelgears.
 4. In combination with a power train for a vehicle wherein apropeller shaft transmits rotational energy from a transmission of aninternal combustion engine to a differential, the improvement whichcomprises a gear ratio multiplier assembly operatively connected betweensaid transmission and said propeller shaft, said gear ratio multiplierassembly having an input shaft geared to an output shaft so that onerotation of said input shaft will result in more than one rotation ofsaid output shaft, said input shaft being joined to said transmission soas to be rotated thereby, and said propeller shaft being joined to saidoutput shaft so as to be rotated thereby.
 5. A method for multiplyingthe gear ratio of a vehicle power train, which comprises the steps of:providing an internal combustion engine; providing a transmission andjoining said transmission to said internal combustion engine; providinga gear ratio multiplier assembly having an input shaft geared to anoutput shaft so that one rotation of said input shaft will result inmore than one rotation of said output shaft; joining said input shaft tosaid transmission so as to be rotated thereby; providing a propellershaft having a first end and a second end; joining said first end ofpropeller shaft to said output shaft for rotation therewith; providing adifferential and joining said differential to said second end of saidpropeller shaft; and providing a pair of drive axles and joining saidpair of drive axles to said differential for rotation thereby.
 6. Apower train for an engine driven device, comprising: an engine having anengine output shaft, a gear ratio multiplier connected to the engineoutput shaft, the gear ratio multiplier having an input shaft connectedto a first gear assembly which is a speed reducing, torque increasing,gear assembly having an output of a lower speed and a higher torque thanthat of the engine output shaft, the ratio multiplier further having asecond gear assembly connected to the output of the first gear assembly,the second gear assembly, a higher speed output than the first gearassembly; and a connector for connecting the output of the second gearassembly to the engine driven device.
 7. The power train of claim 6,wherein the engine is connected to the gear ratio multiplier through atransmission.
 8. The power train of claim 7, wherein the engine drivendevice is a vehicle having driven wheels and wherein the connector is adifferential connected between the driven wheels and the gear ratiomultiplier.
 9. A gear ratio multiplier comprising: an input shaftadapted for connection to a source of rotation and torque; a first gearassembly connected to the input shaft, the first gear assembly being aspeed reducing torque increasing gear assembly having an output of alower speed and higher torque than that of the input shaft; a secondgear assembly connected to the output of the first gear assembly, thesecond gear assembly being a speed increasing assembly and having anoutput of a higher speed than the output of the first gear assembly; andan output shaft driven by the second gear assembly, the output shaftbeing adapted for connection to a device driven by the source ofrotation and torque.
 10. The gear ratio multiplier of claim 9, whereinthe first and second gear assemblies comprise planetary gears.
 11. Thegear ratio multiplier of claim 10, wherein the gear assemblies comprisefirst and second level gear assemblies.
 12. The gear ratio multiplier ofclaim 10, wherein the gear assemblies comprise hypoid gear assemblies.13. The gear ratio multiplier of claim 10, wherein the gear assembliescomprise ring gears driving and being driven by pinions.